var moment = require("moment");
var _ = require("lodash");
var fs = require('fs');
var mkdirp = require('mkdirp');
var jade = require('jade');
var markdown = require( "markdown" ).markdown;
var path = require('path');
var schemas = require('./schemas.js');
var config = require("./config.js").config;

var Post = function(data) {
    this.data = this.sanitize(data);
}

////////////////////////////////////////////////////////////////////////////////////////
// Prototype Setup
////////////////////////////////////////////////////////////////////////////////////////

Post.prototype.data = {}

Post.prototype.get = function (name) {
    return this.data[name];
}

Post.prototype.set = function (name, value) {
    this.data[name] = value;
}

Post.prototype.toString = function () {
    return 'Post: ' + this.get('title') + ' - ' + this.getShortDate();
}

Post.prototype.sanitize = function (data) {
    data = data || {};
    schema = schemas.post;
    return _.pick(_.defaults(data, schema), _.keys(schema));
}

Post.prototype.save = function (date, callback) {
    var self = this;
    if (date) {
        this.set("updatedDate", date);
    } else {
        this.set("updatedDate", new Date());
    }
    this.data = this.sanitize(this.data);
    db.collection("posts").update({uuid: this.get("uuid")}, this.data, {upsert: true}, function(err) {
        callback(err);
    });
}


////////////////////////////////////////////////////////////////////////////////////////
// Prototype Functions
////////////////////////////////////////////////////////////////////////////////////////

// Parse a string of tags
// Returns a list of tags
Post.prototype.tagPost = function(str) {
    this.set("tags", []);

    // we don't need no stinking commas
    var str = str.replace(/,/g,'');

    // remove accents, swap ñ for n, etc
    var from = "àáäâèéëêìíïîòóöôùúüûñç·/,:;&%";
    var to   = "aaaaeeeeiiiioooouuuunc-------";
    for (var i=0, l=from.length ; i<l ; i++) {
        str = str.replace(new RegExp(from.charAt(i), 'g'), to.charAt(i));
    }

    // Make into a sorted, unique array
    var l = str.split(" ");
    var list = []
    for (i = 0; i < l.length; i ++) {
        if (l[i]) {
            list[i] = l[i].toLowerCase().trim()
        }
    }
    list = list.sort();
    var unique = list.filter(function(elem, index, self) {
        return index == self.indexOf(elem);
    })

    // Push these into the post.
    for (var i = 0, size = unique.length; i < size; i++) {
        if (unique[i]) {
            this.data.tags.push({name: list[i]});
        }
    }
}

// Function to get a YYYY-MM-DD format of the current postDate
// Arguments: None
// Returns: Date as String
Post.prototype.getShortDate = function () {
    return moment(this.get("postDate")).format("YYYY-MM-DD");
}

// Function to return rendered markdown of a post
// Arguments: None
// Returns: Content as String
Post.prototype.renderMarkdown = function () {
    return markdown.toHTML(this.get("markdown"));
}

// Function to get the relative url of a post, this sets the permalink structure
// Arguments: None
// Returns: URL as String
Post.prototype.getURL = function () {
    var url  = "/blog/";
        url += moment(this.get("postDate")).format("YYYY/MM/");
        url += this.get("slug") + '/';
    return url;
}

// Function to return the path of the post file
// Arguments: None
// Returns: Path as a string
Post.prototype.getFilePath = function () {
    var file = path.join(this.getDirectory(),'index.html');
    return file;
}

// Function to return the post build directory
// Arguments: None
// Returns: Directory path as String
Post.prototype.getDirectory = function () {
    var dir = path.join(config.buildDir,this.getURL());
    return dir;
}


// Build a slug from a title string
// Arguments: None
// Returns: Post Slug as String
Post.prototype.makeSlug = function () {
      str = this.get("title").replace(/^\s+|\s+$/g, ''); // trim
      str = str.toLowerCase();
      str = str.trim();

      // remove accents, swap ñ for n, etc
      var from = "àáäâèéëêìíïîòóöôùúüûñç·/_,:;&";
      var to   = "aaaaeeeeiiiioooouuuunc-------";
      for (var i=0, l=from.length ; i<l ; i++) {
        str = str.replace(new RegExp(from.charAt(i), 'g'), to.charAt(i));
      }

      str = str.replace(/[^a-z0-9 -]/g, '') // remove invalid chars
        .replace(/\s+/g, '-') // collapse whitespace and replace by -
        .replace(/-+/g, '-'); // collapse dashes

      return str;
};

// Function to build static renderings of a particular post.
// Arguments: Callback function
// Returns: err
Post.prototype.build = function (callback) {
    console.log('Rendering ' + this);

    year = moment(this.get("postDate")).format("YYYY");
    month = moment(this.get("postDate")).format("MM");

//     Post.buildYearIndex(year, function (err) {
//         if (err) console.log(err);
//     });
    Post.buildMonthIndex(year, month, function (err) {
        if (err) console.log(err);
    });

    var options = {
        pretty: true,
        post: this
    };

    var jadeOut = jade.renderFile('views/render-post.jade', options);

    self = this;

    mkdirp(self.getDirectory(), function (err) {
        if (!err) {
            fs.writeFile(self.getFilePath(), jadeOut, 'utf-8', function (err) {
                if (!err) {
                    self.set('lastBuildDate', new Date());
                    self.save(self.get('lastBuildDate'), function (err) {
                        callback(err);
                    });
                } else {
                    callback(err);
                }
            });
        } else {
            callback(err);
        }
    });
}


////////////////////////////////////////////////////////////////////////////////////////
// Independent Functions
////////////////////////////////////////////////////////////////////////////////////////



// Function to find the most recent post generation.
// Returns a date object
Post.getLastBuildDate = function (callback) {
    db.collection("posts").findOne({}, {lastBuildDate: 1}, {sort: {lastBuildDate: -1}},
        function(err, doc) {
            callback(err, doc.lastBuildDate);
        }
    )
};

// Function to find the most recent post upload date.
// Returns: err, date object
Post.getLastUploadDate = function (callback) {
    db.collection("posts").findOne({}, {lastUploadDate: 1}, {sort: {lastUploadDate: -1}},
        function (err, doc) {
            callback(err, doc.lastUploadDate);
        }
    )
};


// Get a specific post by it's UUID
// Returns: err, post object
Post.getByUUID = function (uuid, callback) {
    db.collection("posts").findOne({uuid: uuid}, function(err, doc) {
        post = new Post(doc);
        console.log('Retrieved ' + post);
        callback(err, post);
    });
}

// Function to get a count of current posts
// Returns: err, count of posts
Post.countPosts = function(callback) {
    db.collection("posts").find({}).count(function (err, count) {
        if (err) console.log(err);
        callback(err, count);
    });
}

// Function to get a list of posts of a certain count and starting at an offset
// Count and start are optional, when start is specified count must be specified.
// Returns: err, list of post objects
Post.getPosts = function(count, start, callback) {
    if (typeof callback === undefined) {
        if (typeof start === undefined) {
            callback = count;
            count = undefined;
            start = undefined;
        }
        else {
            callback = start;
            start = undefined;
        }
    }

    var options = {}
    if (start) options.skip=start;
    if (count) options.limit=count;
    options.sort = [['postDate', 'desc'],['title', 'asc']];

    db.collection("posts").find({},options).toArray( function(err, docs) {
        if (!err) {
            posts = [];
            for (i=0; i<docs.length; i++) {
                posts.push(new Post(docs[i]));
            }
            callback(null, posts);
        } else {
            console.log(err);
            callback(err, null);
        }
    });
}

// Function to find posts that need to be built
// Inputs: Callback function
// Returns: err, list of Post objects
Post.getNeedsBuild = function (callback) {
    db.collection("posts").find({
            $where: "(this.lastBuildDate < this.updatedDate) && this.published"
        }).toArray(
        function (err, docs) {
            if (err) console.log(err);
            posts = [];
            for (i=0; i<docs.length; i++) {
                posts.push(new Post(docs[i]));
            }
            callback(null, posts);
        }
    );
}

// Function to find posts that need to be uploaded
// Inputs: Callback function
// Returns: err, List of Post objects
Post.getNeedsUpload = function (callback) {
    db.collection("posts").find({
            $where: '(this.lastUploadDate < this.updatedDate) && \
                     (this.lastBuildDate >= this.updatedDate) && \
                      this.published'
        }).toArray( function (err, docs) {
            if (err) console.log(err);
            posts = [];
            if (docs) {
                for (i=0; i<docs.length; i++) {
                    posts.push(new Post(docs[i]));
                }
                callback(null, posts);
            } else {
                callback("No posts require upload.", null);
            }
        }
    );
}

// Function to build an index for a specific month
// Inputs: Year, Month, callback
// Returns: err
Post.buildMonthIndex = function (year, month, callback) {
    console.log('Rendering month index: '+year+'/'+month);

    directory  = config.buildDir
    directory += "/blog/";
    directory += year + '/' + month + '/';

    console.log('Finding posts from '+year+'/'+month);
    mkdirp(directory, function (err) {
        if (!err) {
            db.collection('posts').find({
                $where: '(this.postDate >=  new Date('+year+', '+month+'-1, 1, 0, 0, 0)) \
                        && (this.postDate <= new Date('+year+', '+month+', 0, 23, 59, 59))'
                }, {sort: [['postDate', 'desc'],['title', 'asc']]}
            ).toArray(function (err, docs) {
                if (!err) {
                    console.log('Found '+docs.length+' posts from '+year+'/'+month);
                    posts = []
                    for (i=0; i<docs.length; i++) {
                        posts.push(new Post(docs[i]));
                    }

                    var jadeOut = jade.renderFile('views/render-post-index.jade', {
                        pretty: true,
                        posts: posts,
                        title: 'Posts from '+year+'/'+month
                    });

                    file = path.join(directory, 'index.html');

                    fs.writeFile(file, jadeOut, 'utf-8', function (err) {
                        callback(err);
                    });
                } else {
                    callback(err)
                }
            });
        } else {
            callback(err);
        }
    });

}

// Function to build an index for a specific year
// Inputs: Year, callback
// Returns: err
Post.buildYearIndex = function (year, callback) {
    console.log('Rendering year index: '+year);

    directory  = config.buildDir
    directory += "/blog/";
    directory += year + '/';

    start = new Date(year, 0, 1, 0, 0, 0);
    end = new Date((year+1), 0, 0, 23, 59, 59);
    console.log('Finding posts between '+start+' and '+end);

    mkdirp(directory, function (err) {
        db.collection('posts').find({
            $where: '(this.postDate >= start) && (this.postDate <= end)'
        }).toArray(function (err, docs) {
            posts = []
            for (i=0; i<docs.length; i++) {
                posts.push(new Post(docs[i]));
            }
            var options = {
                pretty: true,
                posts: posts,
                title: 'Posts from '+year
            };
            var jadeOut = jade.renderFile('views/render-post-index.jade', options);

            file = path.join(directory, 'index.html');

            fs.writeFile(file, jadeOut, 'utf-8', function (err) {
                callback(err);
            });
        });
    });

}

// Export the Post object for external use.
module.exports = Post;